1. Field of the Invention
The present invention relates to a laser television, and more particularly to a laser television having a means for controlling a speckle phenomenon caused by different wavelengths of light.
2. Description of the Related Art
In general, image regeneration apparatuses including projection and laser televisions have a plurality of lasers for generating interferential light of basic colors, e.g., red, green, and blue, so that color images can be displayed on a screen. In other words, the image regeneration apparatuses can display color images using a combination of different wavelengths of light.
The lasers generate different wavelengths of light, the high degree of interference of which causes irregular intensity distribution when images are displayed on screens.
The irregular intensity distribution on laser televisions' screens due to the high degree of interference of light is referred to as “speckle noise.” Speckle noise may occur when the screens are not even or when fine dust exists in the propagation path of light.
In an effort to remove the speckle noise, it has been proposed to position ground glass in the propagation path of light and to vibrate the ground glass minutely, so that the speckle noise on the screens can be suppressed. However, when light passes through the ground glass, a large loss of intensity occurs.
As an alternative to the ground glass scenario, it is proposed to use a diffraction grating, which has a higher transmission coefficient for interferential light than the ground glass. The intensity loss for interferential light can then be decreased.
However, a means for removing speckle noise including a diffraction grating has a problem in that it must include a plurality of diffraction gratings, which have different grating cycles corresponding to different wavelengths of interferential light. This increases the manufacturing cost and makes it difficult to align optical axes.